Tony Vargas
Legend
That's actually my preference. Some situations - say you're raiding an enemy stronghold and you're highly motivated to secure some key objective - a short rest might be just catching your breath between encounters, and a long rest is out of the question. Others - long sea voyage, since I've used it a lot - short rest is anything from an hour to a few days, it doesn't matter because encounters are days if not weeks apart, but age-of-sail voyages are a hardship, even the best supplied ship gets you some malnutrition going, for just one instance, so long rests are restricted to putting into port of foraging on a pleasant island with fresh water. All sorts of room in-between for scenarios with very different pacing, and different criteria for 'rest' that make sense in their context.You could try would be variable recovery rates but that seems like a much worse solution than the one I'm suggesting. It ties resting to fictional events and then fails to make those events consistent. UGH! That's worse IMO than tying recovery to no in fiction event at all.
But whether that's fiction-driven or rationalization-of-mechanics-driven, you're still stuck with the need to get a certain net pacing of encounters (or other stress on resources) between rests, because of the game's design.